In a massively distributed storage system, objects are used as a basic storage form in most cases, where an object is a set of both data and self-descriptive information and is a basic storage unit for storing data in a disk, and a consistent hashing algorithm generally needs to be used to implement disperse distribution of these objects. Although the consistent hashing algorithm ensures balance, dispersibility, error tolerance, scalability, and the like for storage of system data, the consistent hashing algorithm does not ensure absolute balance. In particular, in a case in which there is a relatively small quantity of physical nodes, objects cannot be evenly mapped to the nodes. To solve this problem, the consistent hashing algorithm introduces a concept of a virtual node. The virtual node is a duplication of a physical node in annular space, and one physical node is corresponding to several virtual nodes. By increasing or expanding a quantity of virtual nodes, balance of the algorithm is greatly improved.
In the prior art, a massive storage system generally uses hard disks of a same capacity to establish a storage cluster and allocates virtual nodes of a same quantity to each physical node, so that the nodes maintain, to a greatest extent, a synchronous growth in terms of storage capacity.
With the continuous development of a hard disk technology, a capacity of a single disk increases continuously, and the massive storage system inevitably faces a problem of hard disk capacity heterogeneous during expansion and parts replacement. However, a current storage solution cannot support hard disk capacity heterogeneousness in massive storage, thereby reducing use experience of a product.